DESCRIPTION: Recently, New Photonics LLC (NP) demonstrated that newly developed blue Light Emitting Diodes (LEDs) used in continuous mode can provide up to 4 mm depth of cure in Dental composite resin in about 2 minutes of exposure. Despite its many advantages, the commercial viability of this LED-based technology would be significantly enhanced if the time of exposure necessary for curing is reduced to a few seconds. The application proposes to investigate the use of LEDs in a pulsed mode as a source of optical radiation for curing Dental composite resins. The spectral output of the widely available blue-green LEDs peaks at the excitation maximum of the camphorquinone photoinitiators used in most Dental composites. The luminous output of the LEDs is entirely within the absorption band of the photoinitiators. Use of pulsed LEDs is an attractive option because it may allow for fine-tuning of the pulse timings to suitably match the photopolymerization dynamics thus reducing cure time to what is currently achieved with lasers. NP will develop a pulsed LED curing system and investigate the curing characteristics (depth of cure, degree of conversion of monomers to polymer, hardness, time of exposure, thermal load) of Dental resins cured using pulsed LEDs.